|
|
Design of knee joint simulator
Polnický, Vojtěch ; Čížek, Petr (referee) ; Vrbka, Martin (advisor)
The diploma thesis is focused on the design and realization of an experimental device. The purpose of device is the simulation of dynamic and kinematic conditions of knee replacement during the walking cycle. The simulator will be used to study the formation of the lubricating film in contact of the femoral component and the polyethylene spacer, and to the cyclic wear tests for knee replacements. First part of thesis is focused on the description of working parameters of knee replacements and analysis of knee joint simulators. The description of conceptual design and selection of the final variation follows. The final design allows simulation of dynamic and kinematic conditions of ISO 14 243-3. Creation of lubricating film is analyzed by the non-contact optical fluorescence microscopy method. The work includes complete drawing documentation, wiring diagram, verification of the functionality of the device and detailed operating instructions.
|
|
|
THE BIOCHEMICAL PROCESS OF LUBRICANT FILM FORMATION INSIDE HIP JOINT REPLACEMENT
Rufaqua, Risha ; Ruggiero,, Alessandro (referee) ; Muoz, Anna Neus Igual (referee) ; Vrbka, Martin (advisor)
The dissertation thesis deals with the lubricant film formation chemistry on hip implant material surfaces with synovial fluid components. Biochemical and tribological properties of synovial fluid after joint replacement are focused, precisely on the chemical composition of the formed lubricating film and chemical structural changes of the associated constituents under mechanical loading. Nevertheless, the synovial fluid components‘ chemical structural changes after the joint replacement are rarely addressed and require further attention. Including metal and ceramics, various combination implant materials were applied within the lubricants of synovial fluid constituents separately and different model synovial fluids to reveal the biochemical reactions and frictional coefficients for understanding the possible lubrication mechanism. Raman Spectroscopic technique is manifested as the most appropriate method to explain the biochemical behaviour of synovial fluid and chemisorption on the surface of the implant material. The method is depicted presenting two different studies focusing on the chemical structure of the synovial fluid film on the implant surface and frictional coefficient measurement of the contact pair within the artificial hip joint. This latest methodological precedent also facilitates to evaluate the chemical structural change of the synovial fluid due to the tribological activity in the hip prosthesis. The thesis expounds original results concerning biotribology to increase the depth of knowledge on joint replacement procedure and to enhance the longevity of the orthopaedic implantations.
|
|
|
Study of Friction in Hip Joint Replacements
Balounová, Hana ; Dzimko, Marián (referee) ; Vrbka, Martin (advisor)
Diploma thesis deals with analysis of coefficient of friction in total hip prosthesis for several materials bearing with presence of bovine serum as substitute of synovial fluid occurred in natural joint. Behavior of coefficient of friction is observed on Mini Traction Machine. Results are plotted at graphs representing dependence of coefficient of friction on time. There are described effects of several kinematic conditions, the influence of used material and the effect of the method of contact lubrication. The experiments analyze how the formation of lubricant film with a layer of adsorbed protein affects coefficient of friction.
|
|
|
Design and realization of tutorial based on SEW Eurodrive gearmotors
Kantor, Martin ; Prášil, Ludvík (referee) ; Vrbka, Martin (advisor)
The thesis deals with a construction of solar tracker designed from the MayTec Profile System using SEW Eurodrive’s electric actuation and accessories. The work describes the design of a laboratory assignment which uses these elements. In the preface information is provided about the construction of solar trackers on which the thesis is based. The next parts of the text are dedicated to each step of the construction design and its variants. A description of how to activate the drive and the design of the connection scheme are also included as well as the technological and construction evaluation. The conclusion contains an economical evaluation of the whole construction.
|
|
| |
|
|
Mapping of lubricating film thickness of human big joints replacements
Bosák, Dalibor ; Hartl, Martin (referee) ; Vrbka, Martin (advisor)
This master’s thesis describes mechanism of lubricating film forming and its thickness in contact of a metal hip joint ball and a glass disc with chromium layer with presence of bovine serum as substitute of synovial fluid occured in a natural joint. Lubricating film thickness is evaluated by a thin film colorimetric interferometry, results are ploted at graphs representing dependence of lubricating film thickness on experiment duration or on mutual speed of articulating surfaces. There is described the influence of concentration of bovine serum and different kinematic conditions on lubricating film forming. From observed interferograms is apparent the adsorption of proteins to glass disc and femoral head surfaces, denaturation and formation of protein aggregations affecting the residual lubricating film thickness.
|
|
|
Generation of Energy Using Renewable Resources
Vrbka, Martin ; Langerová, Petra (referee) ; Froehling, Kenneth (advisor)
Tato bakálářská práce se zaměřuje na výrobu elektrické energie za pomoci obnovytelných zdrojů. Existuje nespočet faktorů vztahůjících se k obnovitelné energii. Nicméně na tyto aspekty je většinou pohlíženo spíše individuálně, než jako na celek. Tudíž se tato práce pokouší obsáhnout většinu významných aspektů jež jsou spojeny s výrobou energie za pomoci obnovitelných zdrojů a organizuje je v jeden logický celek. To je uskutečněno představením obecného popisu technologie jako takové stejně jako výsledných dopadů použitých systémů.
|
|
|
Tribology of hydrogels for articular cartilage replacement
Křížová, Michaela ; Ranuša, Matúš (referee) ; Vrbka, Martin (advisor)
The bachelor's thesis deals with the description of the tribological properties of focal joint implants in the place of a cartilage defect. The application of focal implants is aimed at a group of younger patients who have to undergo surgery to repair damaged cartilage, but a total replacement is not suitable for them due to its lifetime. The contact of the focal implant and the opposite cartilage was simulated using metal samples and hydrogel, which has very similar properties to natural cartilage. For a possible comparison of values, a tribological measurement of the cartilage samples against the hydrogel was carried out. This pair serves as a model for defining friction in a healthy joint. The main task of this thesis was to determine the coefficient of friction of Ti6Al4V, Ti6Al4V+DLC, CoCrMo and cartilage against the hydrogel. The experiments were carried out using a tribometer in a pin-on-plate configuration. The Ti6Al4V alloy without coating and with DLC coating came out with the lowest coefficient of friction for both variants, almost identically 0.0526. Higher friction was measured for CoCrMo, but it differed from the titanium alloy to one-hundredth. On the contrary, the highest coefficient of friction was unexpectedly manifested in the cartilage samples, where the lowest friction was assumed. The error was due to poor selection of cartilage samples. The thesis simply describes the tribological behaviour of focal implants and the result is a material with the lowest coefficient of friction. The measurements performed could help further research into the issue of focal implants.
|
|
|
Design of a simulator for studying eye friction and lubrication
Snopek, Lukáš ; Horák, Zdeněk (referee) ; Vrbka, Martin (advisor)
This work deals with the design of a tribometer, which simulates the interaction between the human eye and the eyelid, and simultaneously measures the friction between them and the thickness of the tear film. The tribometer will be used for research and development of artificial tears based on hyaluronic acid. The aim of the work was to design experimental conditions, conceptual and design solutions, as well as to ensure the production, assembly, and validation of the device. The experimental conditions were determined based on critical research. Four different conceptual solutions were proposed, of which two were selected for further development in the design solution. Based on the engineering documentation, the production of non-standardized components and assembly were ensured. Validation experiments demonstrated that the simulator enables the measurement of friction and tear film thickness at the contact area under the desired conditions, with both conforming and non-conforming types of contact. The contribution of this work lies in the construction of a new device that allows for measuring the coefficient of friction and film thickness during conforming contact, offering new opportunities in the study of human eye biotribology.
|
|
|
Friction and lubrication of fascia
Chmelík, Jiří ; Daniel, Matej (referee) ; Vrbka, Martin (advisor)
The diploma thesis was part of the project "Regeneration and lubrication of fascia with hyaluronan" of the company Contipro a.s., whose main goal is the development of an injectable medicinal product. The number of patients suffering from so-called myofascial lower back pain is increasing. The cause of the pain is increased hyaluronic acid, which is produced between the layers of the fascia. If the viscosity is low, the fascia layers are not affected and the coefficient of friction is low. The purpose of the product is to improve the sliding movement of the fascia and relieve patients of pain. The main component of the medicine is hyaluronic acid. The project included rheological and tribological analysis of hyaluronic acid samples. A tribological model of fascia in a pin-on-plate configuration was created for the analysis of the coefficient of friction. Based on the fascia models used, the dependence between the coefficient of friction and viscosity of native hyaluronic acid solutions was found. For models and real fascias, the native solution (Bonharen) was found to have better friction properties than hyaluronic acid derivatives. These analyzes have contributed not only to the development of the drug, but also to the emergence of other studies that would like to address the biotribology of fascia.
|
guest ::
